Degradation Characteristics Of 1,2,3,4-Tetrachlorobenzene By A Selected Dominant Bacterial Strain

With the rapid development of industry, organic pollutants has become a serious problem. Chlorobenzens (CBs) is a kind of basic material of chemical industry, which is applied into the different areas in industry and agriculture. With widely used, more and more CBs entered environment and accumulated there. The prevention of CBs is especially important due to its toxicity and the difficulty of degradation.Internal and overseasresearch on the biodegradation of CBs has obtained the certain result, many scholars have screened or found strains which can degradation CBs. But those research almost about trichlorobenzene、pentachlorobenzene、hexachlorobenzene, and the intermediate product of the degradation of pentachlorobenzene and hexachlorobenzene often found the tetrachlorobenzens (TeCB). It undoubtedly produces more pressing demands on the degradation of TeCB。But currently the research of TeCB, especially 1,2,3,4-TeCB degradation research has been reported rarely. This issue focus on the degradation characteristics of 1,2,3,4-Tetrachlorobenzene by a selected dominant bacterial strain. And research the effective factors such as temperature、pH、 1,2,3,4-TeCB concentration、ininoculation were investigated.A bacterial strain named L-1 was screened, isolated, and purified from surrounding soil of a chemical reagents factory in Guangdong Province, which had degradation capacity of 1,2,3,4-TeCB. Analysis of different reaction conditions (temperature, pH,1,2,3,4-TeCB, inoculation concentrations) on degradation effect of impact and optimize the degradation conditions. The degradation characteristics of 1,2,3,4-Tetrachlorobenzene (1,2,3,4-TeCB) in wastewater were studied by the chemical oxygen demand (COD), chlorion release concentration, and degradation rate of 1,2,3,4-TeCB in waste water at various strain inoculation concentrations (2%,3%,5%, respectively). The degradation products of 1,2,3,4-TeCB by train L-1 were analyzed by GC-MS workstation. The results showed strain L-1 was Bacillus subtilis as identified by partial length of 16s rDNA sequences. The optimal strain inoculation concentration was 5%.The degradation rate of COD was up to 62.71%, the chloridion release concentration was 4.98mg/L, the degradation contents of 1,2,3,4-TeCB was up to 21.47 mg/L at the condition of pH7.0,30℃, rotate speed 110 r/min after 7 days. By analysis of degradation products of 1,2,3,4-TeCB by GC-MS, it suggested that the degradation pathway of 1,2,3,4-TeCB was benzene ring opened firstly, the chloride ions removed from the parent molecule then.